This invention relates to a method and apparatus for collecting and analyzing a sample. More particularly, this invention relates to a method and apparatus having a sample collection means which can be positioned and retained directly on a means for effecting analysis of the sample which can include a sample incubation means.
Prior to the present invention, bioassays such as antigen-antibody reactions, ligand-receptor assays, enzyme-substrate reactions, hybridization nucleic acid reactions, DNA, RNA lectin or the like have been analyzed in apparatus which permits or excludes a sample incubation step. Generally, a receptor is directly bound, by such means as covalently or hydrostatically or indirectly bound, by such means as by being attached to latex particles or magnetic particles and trapped in or on a porous substrate such as a microporous membrane. The sample then is contacted with the membrane so as to effect binding of the ligand to the receptor. The liquid portion of the sample is removed from contact with the membrane and reagents then are introduced in order to determine the presence and/or quantify of the ligand in the sample. Generally, detection of the ligand is determined with a labeled reactant wherein the label can be an enzyme, radionuclide, fluorescent moiety or the like.
It has been proposed in U.S. Pat. No. 4,246,339 to provide a multiwell test device for analyzing a plurality of sample simultaneously. The device includes an upper member having a plurality of wells each having a microporous membrane sealed thereto and having a receptor bound thereon. A bottom member is provided which contains a sorbent material for liquids, a biasing means is interposed between the top and bottom members to bias the membranes away from contact with the sorbent material so that a sample introduced into a well can be incubated in contact with the receptor prior to removing liquid from the wells. Upon completion of incubation, the membranes are contacted with the sorbent material so that filtration of the sample is effected by capillary action. The samples are introduced indirectly into the wells such as with a pipette, or a dropper. This apparatus is not capable of collecting a sample directly such as from a patient or the environment and therefore is undesirable.
U.S. Pat. No. 4,727,019 discloses an apparatus for effecting a ligand receptor assay comprising a top member having a well to which is sealed a microporous membrane. A receptor is bound to the top surface of the membrane. A bottom member is provided which contains a sorbent material for liquids. The top and bottom members are positioned so that the sorbent material always contacts the bottom surface of the membrane. This apparatus is undesirable since it does not permit incubation of the sample in contact with the receptor. This is because the sample introduced into the well immediately is filtered by the membrane due to capillary action by the sorbent material. In addition, the apparatus does not permit collecting a sample directly but requires the use of an intermediary means such as a pipette or dropper. This is undesirable since the sample must be handled a multiplicity of times and may contain dangerous components such as hepatitus virus, human immune virus, (HIV) which can cause acquired immune deficiency syndrome (AIDS).
Accordingly, it would be desirable to provide a method and apparatus which permits sample collection, sample concentration and analysis with a single apparatus. Such a method and apparatus would permit a one step sample collection and analyses with a minimum of sample handling. This, in turn, would improve safety for the sample collection and analysis tasks.